code: def testAintDiff(self):
      location = array.array("i", range(10))
      base = MPI.Get_address(location)
      addr1 = base + 8
      addr2 = base + 4
      diff = MPI.Aint_diff(addr1, addr2)
      self.assertEqual(diff, 4)
  
file_path: mpi4py/test/test_address.py
imports: from mpi4py import MPI
  import mpiunittest
  from arrayimpl import array, numpy
label_desc: Use image node_id 6 for calling the TestAddress obj's underlying member method code with example usage: obj.testAintDiff() without return types